. >> to honor the memory of nelson mandela, president obama has ordered flags to be flown at half staff at the white house and all publi buildings. >> tonight, the tributes in his honor. but let's begin with more on the growing crowds outside mandela's home in johannesburg. >>> nelson mandela's suburban mansion in johannesburg. the crowds have been building the last few hours, singing songs of the anti-apartheid struggle, singing the south african national anthem. late in the evening, the south african president went on national television and broke the news. and in doing so, broke the hearts of millions of south africans. >> our nation has lost its greatest son. our people have lost a father. >> nelson mandela went into hospital six months ago, first seriously ill, then critically ill, then he was returned to his home here in september where he was receiving the same level of care as he did in the hospital. so this day was not unpredictable, but painful nonetheless. the father of this nation, nelson mandela, dead at the age of 95. nbc news, johannesburg. >> our team coverage continues